I think they mean black box to the person paying and the one being paid not to Instacart. Though this is kind of frustrating. Because 99%+ Instacart themselves

I think they mean black box to the person paying and the one being paid not to Instacart. Though this is kind of frustrating. Because 99%+ Instacart themselves knew what the formula is. I give a 1% change they legitimately did the math wrong and somehow got it through QA and code review into production and a 99% chance they are being intentionally deceptive by calling it an "algorithm glitch".